Fluoroperouskite radiation dosimeters and storage phosphors

ABSTRACT

This invention provides phosphor-doped fluoroperovskite compounds that are capable of storing at least part of the energy of incident ionizing radiation and releasing at least part of the stored energy upon optical stimulation or heating. Also provided are dosimeters and radiation storage devices comprising the compounds, methods of preparing the compounds, and methods of using the compounds to determine a dose of ionizing radiation or to record and reproduce an ionizing radiation image.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present patent application is a nationalization of Internationalapplication No. PCT/NZ08/000,160, filed Jul. 7, 2008, published inEnglish, which is based on, and claims priority from, _U.S._ApplicationNo. 60/929,626, filed Jul. 5, 2007, both of which are incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The invention relates to radiation dosimeter and storage phosphormaterials. More particularly, but not exclusively, it relates tofluoroperovskites doped with optically active ions for the detection ofionizing radiation by optically stimulated luminescence (OSL) andthermally stimulated luminescence (TSL).

BACKGROUND OF THE INVENTION

TSL dosimeters (for example, LiF) are widely used for accuratemeasurements of the radiation dose upon exposure to ionizingradiation—for example, X-rays, gamma rays, beta particles, alphaparticles and neutrons. The ionizing radiation leads to trappedelectrons and holes. The dose information is read by heating thedosimeter at a controlled rate to high temperatures. The integratedemitted luminescence intensity can be used to determine the radiationdose. This type of dosimeter typically requires an expensive reader andthe dose information can only be read once.

OSL dosimeters (for example, Al₂O₃:C) have recently been developed.Exposure to ionizing radiation leads to trapped electrons and holes. TheOSL read-out process is via exposure to light, and the emitted lightintensity provides the dose information. This type of dosimeter has theadvantage that dose information can be read by optical means, and noheating is required. For personal dosimeters, it is advantageous if theeffective atomic number (Z_(eff)) is close to that of tissue, for whichZ_(eff)=7.42.

X-ray storage phosphors, such as those disclosed in U.S. Pat. No.3,859,527, are substitutes for X-ray film, which may be used inindustrial and Medical imaging. They are formed as screens of powderedcrystalline phosphor material—BaFBr doped with ˜1000 ppm Eu²⁺ is themost common material—with the crystal grains held in place by atransparent binder. Upon exposure to X-rays, electron-hole pairs arecreated in the crystalline material and the electrons and holes can beseparately trapped at defect and impurity sites. The spatialdistribution and concentration of trapped electrons and holes representsa two-dimensional stored image of the incident X-ray intensity and henceof any object that is placed in the X-ray beam.

Recombination of the electrons and the holes can be stimulated byilluminating the material with red light that promotes one or othercarrier to the conduction or valence band, where it is free to move torecombine with the conjugate charge carrier. The recombination energy isemitted in the form of a visible photon, which may be detected with aphotomultiplier. This stimulation process is called optically stimulatedluminescence.

If the stimulation is provided by a raster-scanned red laser beam, thenthe photo-stimulated luminescence intensity follows that of the X-rayimage. The read-out process is destructive in nature, but the imagingplate can then be re-used. The primary disadvantages are poorerresolution and greater initial cost as compared to X-ray film. Theimaging plates also have a dark decay, which means that the image mustbe read-out within 24 hours.

The perovskites are a general group of compounds which have the samecrystal structure. The basic chemical formula follows the pattern ABO₃,where A and B are cations of different sizes (for example, CaTiO₃). Thegeneral crystal structure is a primitive cube, with the A-cation in themiddle of the cube, the B-cation in the corner and the anion, commonlyoxygen, in the centre of the face edges.

The fluoroperovskites are analogous compounds of the composition AMF₃,wherein A is an alkali metal and M is an alkaline earth or transitionmetal.

Divalent and trivalent fluorides, such as those disclosed in U.S. Pat.No. 5,028,509, are known to display OSL. Such fluorides may be used inapplications that include X-ray imaging plates (see, for example, U.S.Pat. No. 3,859,527) and thermal neutron imaging plates (see, forexample, U.S. Pat. No. 5,635,727).

Some fluoroperovskites are also known to display OSL and TSL and hencethey have potential applications in dosimetry and radiation imaging.U.S. Pat. No. 6,583,434 discloses that RbCdF₃:Mn²⁺, RbMgF₃:Mn²⁺,CsCdF₃:Mn²⁺ and CsMgF₃:Mn²⁺ display OSL after X-ray irradiation andstimulation with light at 266 nm. No OSL was observed from NaMgF₃:Mn²⁺.

U.S. Pat. No. 7,141,794 discloses fast photo-luminescence fromscintillator compositions comprising a halide perovskite activated withCe³⁺ or Pr³⁺.

It is an object of the present invention to provide compounds for use asradiation dosimeters and/or storage phosphors; and/or to overcome one ormore of the above-mentioned disadvantages; and/or to at least providethe public with a useful choice.

Other objects of the invention may become apparent from the followingdescription, which is given by way of example only.

In this specification where reference has been made to patentspecifications, other external documents, or other sources ofinformation, this is generally for the purpose of providing a contextfor discussing the features of the invention. Unless specifically statedotherwise, such references are not to be construed as an admission thatsuch external documents, or such sources of information, in anyjurisdiction, are prior art, or form part of the common generalknowledge in the art.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, wherein the phosphor-dopedfluoroperoyskite compound is selected from the group consisting of:

-   -   Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺;        Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺;        and wherein (x+x′)≦0.1, y≦0.1 and z≦0.3;

K_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+) whereinZ^(d+) is the dopant phosphor ion and is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; andTb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 andz≦0.3; and

Rb_(1−(x+x))Na_(x)K_(x),Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+) whereinZ^(d+) is the dopant phosphor ion and is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; andTb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 andz≦0.3;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is selected from the group consisting of: Eu²⁺;Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Mn²⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earthmetal ions: Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;and Pb²⁺.

In a second aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, wherein the phosphor-dopedfluoroperovskite compound is selected from the group defined above, withthe proviso that the phosphor-doped fluoroperovskite compound is notNaMgF₃:Eu²⁺ or NaMgF₃:Mn²⁺.

In a third aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:

-   -   Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Sm²⁺; Sm³⁺;        Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein        (x+x′)≦0.1, y≦0.1 and z≦0.3;    -   K_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺;        Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺;        and wherein (x+x′)≦0.1, y≦0.1 and z≦0.3; and    -   Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)CL;Z^(d+) wherein        Z^(d+) is the dopant phosphor ion and is selected from the group        corilsting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺;        and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺;        Ce³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein        (x+x′)≦0.1, y≦0.1 and z≦0.3;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Pr³⁺ or Tb³⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis K_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earthmetal ions: Sm²⁺, Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺, and Tb³⁺; and Tl⁺; In⁺; Ga⁺;and Pb²⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺.

In an alternative embodiment, wherein the phosphor-dopedfluoroperovskite compound isRb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), the dopantphosphor ion is selected from the group consisting of: the transitionmetal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rare earth metalions: Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺ or Ce³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z);Z^(d+),the dopant phosphor ion is Pr³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is K_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Ce³⁺.

In one embodiment, x, x′, y and z are all about 0.

In a fourth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:

-   -   NaMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal        ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;        and Pb²⁺;    -   KMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal        ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;        and Pb²⁺; and

RbMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is selectedfrom the group consisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺;Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺;Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is selected from thegroup consisting of: Eu²⁺; Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:e, the dopant phosphot fOnd Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Mn²⁺.

In a preferred embodiment, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.2% Eu²⁺;NaMgF₃:0.1% Pr³⁺; NaMgF₃:0.2% Tb³⁺; NaMgF₃:0.2% Mn²⁺; KMgF₃:0.2% Eu²⁺;RbMgF₃:0.2% Eu²⁺; and RbMgF₃:0.2% Ce³⁺.

In a preferred embodiment, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.2% Eu²⁺;NaMgF₃:0.1% Pr³⁺; NaMgF₃:0.2% Tb³⁺; NaMgF₃:0.2% Mn²⁺; KMgF₃:0.2% Eu²⁺;and RbMgF₃:0.2% Ce³⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is NaMgF₃:0.2% Eu²⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is RbMgF₃:0.2% Eu²⁺.

In a fifth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:

-   -   NaMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions:        Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tr; In⁺; Ga⁺; and Pb²⁺;    -   KMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal        ions: Eu²⁺; Sm²⁺; Sm³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and        Pb²⁺; and    -   RbMgF₃:Z^(d+) wherein Zd⁺ is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions:        Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;        and Pb²⁺;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Pr³⁺ or Tb³⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis KMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺;and Tb³⁺.

In an alternative embodiment, wherein the phosphor-dopedfluoroperovskite compound is RbMgF₃:Z^(d+), the dopant phosphor ion isselected from the group consisting of: the transition metal ions: Cu⁺;Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rare earth metal ions: Sm²⁺; Sm³⁺;Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is RbMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺ or Ce³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Pr³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is KMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is RbMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is RbMgF₃:Z^(d+), the dopant phosphor ion is Ce³⁺.

In a preferred embodiment, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺;KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.1% Pr³⁺;NaMgF₃:0.2% Tb³⁺; KMgF₃:0.2% Eu²⁺; RbMgF₃:0.2% Eu²⁺; and RbMgF₃:0.2%Ce³⁺.

In a preferred embodiment, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺;KMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.1% Pr³⁺;NaMgF₃:0.2% Tb³⁺; KMgF₃:0.2% Eu²⁺; and RbMgF₃:0.2% Ce³⁺

In one embodiment of any of the first to the fifth aspects of theinvention, at least part of the stored energy is released from thephosphor-doped fluoroperovskite compound upon optical stimulation in awavelength range from about 200 nm to about 1000 nm. In one embodiment,the optical stimulation wavelength is from about 290 nm to about 350 nm.In a preferred embodiment, the optical stimulation wavelength is fromabout 300 nm to about 1000 nm. In one embodiment, the opticalstimulation wavelength is about 470 nm. In a further preferredembodiment, the optical stimulation wavelength is in the near infrared(>700 nm). In a further preferred embodiment, the optical stimulationwavelength is about 875 nm.

In a preferred embodiment of any of the first to the fifth aspects ofthe invention, the stored energy is released from the phosphor-dopedfluoroperovskite compound at a wavelength that is shorter than theoptical stimulation wavelength.

In a sixth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon heating, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:

-   -   Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺;        Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺;        and wherein (x+x′)≦0.1, y≦0.1 and z≦0.3; and    -   Rb_(1−(x+x′))Na_(x)K_(x)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth,metal ions: Eu²⁺;        Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺;        and wherein (x+x′)≦0.1, y≦0.1 and z≦0.3;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+);the dopant phosphor ion is selected from the group consisting of: Eu²⁺;Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Mn²⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Mn²⁺.

In a seventh aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon heating, wherein the phosphor-dopedfluoroperovskite compound is selected from the group defined above, withthe proviso that the phosphor-doped fluoroperovskite compound is notNaMgF₃:Eu²⁺, NaMgF₃:Mn²⁺, or RbMgF₃:Mn²⁺.

In an eighth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon heating, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:

-   -   Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Sm²⁺; Sm³⁺;        Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein        (x+x′)≦0.1, y≦0.1 and z≦0.3; and    -   Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+)        wherein Z^(d+) is the dopant phosphor ion and is selected from        the group consisting of: the transition metal ions: Cu⁺; Ag⁺;        Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺;        Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and        wherein (x+x′)≦0.1, y≦0.1 and z≦0.3;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)Cl_(z):Z^(d+), thedopant phosphor ion is Pr³⁺ or Tb³⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Pr³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Eu²⁺.

In one embodiment, x, x′, y and z are all about 0.

In a ninth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon heating, wherein the phosphor-dopedfluoroperovskite compound is selected from, the group consisting of:

-   -   NaMgF₃: Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition, metal        ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal        ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;        and Pb²⁺; and    -   RbMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal        ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;        and Pb²⁺;        and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis NaMgF₃: Zd⁺, the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is selected from thegroup consisting of: Eu²⁺; Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃: Z^(d+), the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃: Z^(d+), the dopant phosphor ion is Mn²⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is RbMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is RbMgF₃:Z^(d+), the dopant phosphor ion is Mn²⁺.

In a preferred embodiment, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Mn²⁺.

In a further preferred embodiment; the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.2% Eu²⁺;NaMgF₃:0.1% Pr³⁺; NaMgF₃:0.2% Tb³⁺; NaMgF₃:0.2% Mn²⁺; RbMgF₃:0.2% Eu²⁺;and RbMgF₃:0.2% Mn²⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is NaMgF₃:0.2% Eu²⁺.

In a tenth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon heating, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:

-   -   NaMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions:        Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺;        and    -   RbMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is        selected from the group consisting of: the transition metal        ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions:        Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and        Pb²⁺;

and mixtures of any two or more thereof.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis NaMgF₃: Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In one embodiment, wherein the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; andTb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Pr³⁺ or Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Pr³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is NaMgF₃:Z^(d+), the dopant phosphor ion is Tb³⁺.

In a preferred embodiment, wherein the phosphor-doped fluoroperovskitecompound is RbMgF₃:Z^(d+), the dopant phosphor ion is Eu²⁺.

In a preferred embodiment, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; andRbMgF₃:Eu²⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.1% Pr³⁺;NaMgF₃:0.2% Tb³⁺; and RbMgF₃:0.2% Eu²⁺.

In a further preferred embodiment, the phosphor-doped fluoroperovskitecompound is RbMgF₃:0.2% Eu²⁺.

In an eleventh aspect, the present invention provides a dosimeter fordetecting ionizing radiation by OSL, comprising a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, wherein the phosphor-dopedfluoroperovskite compound is as defined for any of the first to thefifth aspects of the invention.

In a twelfth aspect, the present invention provides a radiation storagedevice comprising a phosphor-doped fluoroperovskite compound, capable ofstoring at least part of the energy of incident ionizing radiation, andreleasing at least part of the stored energy upon optical stimulation,wherein the phosphor-doped fluoroperovskite compound is as defined forany of the first to the fifth aspects of the invention.

In a thirteenth aspect, the present invention provides a method ofdetermining a dose of ionizing radiation comprising:

-   (a) providing a phosphor-doped fluoroperovskite compound, capable of    storing at least part of the energy of incident ionizing radiation,    and releasing at least part of the stored energy upon optical    stimulation, wherein the phosphor-doped fluoroperovskite compound is    as defined for any of the first to the fifth aspects of the    invention;-   (b) irradiating the phosphor-doped fluoroperovskite compound with    ionizing radiation;-   (c) optically stimulating the irradiated phosphor-doped    fluoroperovskite compound with a predetermined intensity of light    comprising at least one predetermined wavelength;-   (d) measuring the intensity and duration of the optically stimulated    luminescence from the irradiated phosphor-doped fluoroperovskite    compound; and-   (e) relating, by calibration procedures, the intensity and duration    of the optically stimulated luminescence to the dose of ionizing    radiation absorbed by the phosphor-doped fluoroperovskite compound.

In a fourteenth aspect, the present invention provides a method forrecording and reproducing an ionizing radiation image comprising thesteps of:

-   (a) providing a phosphor-doped fluoroperovskite compound, capable of    storing at least part of the energy of incident ionizing radiation,    and releasing at least part of the stored energy upon optical    stimulation, wherein the phosphor-doped fluoroperovskite compound is    as defined for any of the first to the fifth aspects of the    invention;-   (b) causing ionizing radiation to be incident upon the compound    through an object to be imaged, so that the compound stores energy    from the radiation;-   (c) exposing the compound to stimulating light to release the stored    energy as emitted light;-   (d) detecting the emitted light for imaging.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isNa_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: Eu²⁺;Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Mn²⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isRb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected froth the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earthmetal ions: Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺;and Pb²⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isNa_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Pr³⁺ or Tb³⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isK_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, wherein the phosphor-doped fluoroperovskite compound isRb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y) F_(3−z)Cl_(z):Z^(d+) and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺.

In an alternative embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−Z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺ or Ce³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Pr³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis K_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Ce³⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, x, x′, y and z are all about 0.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isNaMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: Eu²⁺; Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Mn²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment of any of the eleventh to thefourteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.2% Eu²⁺;NaMgF₃:0.1% Pr³⁺; NaMgF₃:0.2% Tb³⁺; NaMgF₃:0.2% Mn²⁺; KMgF₃:0.2% Eu²⁺;RbMgF₃:0.2% Eu²⁺; and RbMgF₃:0.2% Ce³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment of any of the eleventh to thefourteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.2% Eu²⁺;NaMgF₃:0.1% Pr³⁺; NaMgF₃:0.2% Tb³⁺; NaMgF₃:0.2% Mn²⁺; KMgF₃:0.2% Eu²⁺;and RbMgF₃:0.2% Ce³⁺.

In a further preferred embodiment of any of the eleventh to thefourteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is NaMgF₃:0.2% Eu²⁺.

In a further preferred embodiment of any of the eleventh to thefourteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is RbMgF₃:0.2% Eu²⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isNaMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Pr³⁺ or Tb³⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isKMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isRbMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺;and Tb³⁺.

In an alternative embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; andTb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺ or Ce³⁺.

In a preferred embodiment of any, of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Pr³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Tb³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis KMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is Ce³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺;KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment of any of the eleventh to thefourteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.1% Pr³⁺;NaMgF₃:0.2% Tb³⁺; KMgF₃:0.2% Eu²⁺; RbMgF₃:0.2% Eu²⁺; and RbMgF₃:0.2%Ce³⁺.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺;KMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.

In a further preferred embodiment of any of the eleventh to thefourteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.1% Pr³⁺;NaMgF₃:0.2% Tb³⁺; KMgF₃:0.2% Eu²⁺; and RbMgF₃:0.2% Ce³⁺.

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, at least part of the stored energy is released from thephosphor-doped fluoroperovskite compound upon optical stimulation in awavelength range from about 200 nm to about 1000 nm. In one embodiment,the optical stimulation wavelength is from about 290 nm to about 350 nm.In a preferred embodiment, the optical stimulation wavelength is fromabout 300 nm to about 1000 nm. In one embodiment, the opticalstimulation wavelength is about 470 nm. In a further preferredembodiment, the optical stimulation wavelength is in the near infrared(>700 nm). In a further preferred embodiment, the optical stimulationwavelength is about 875 nm.

Accordingly, in one embodiment of the thirteenth aspect of theinvention, the at least one predetermined wavelength in step (c) is in arange from about 200 nm to about 1000 nm. In another embodiment, thewavelength is from about 290 nm to about 350 nm. In a preferredembodiment, the wavelength is from about 300 nm to about 1000 nm. In oneembodiment, the wavelength is about 470 nm. In a further preferredembodiment, the wavelength is in the near infrared (>700 nm). In afurther preferred embodiment, the wavelength is about 875 nm.

Accordingly, in one embodiment of the fourteenth aspect of theinvention, the wavelength of the stimulating light in step (c) is in arange from about 200 nm to about 1000 nm. In another embodiment, thewavelength is from about 290 nm to about 350 nm. In a preferredembodiment, the wavelength is from about 300 nm to about 1000 nm. In oneembodiment, the wavelength is about 470 nm. In a further preferredembodiment, the wavelength is in the near infrared (>700 nm). In afurther preferred embodiment, the wavelength is about 875 nm.

In a preferred embodiment of any of the eleventh to the fourteenthaspects of the invention, the energy stored upon irradiation with theincident ionizing radiation is released as optically stimulatedluminescence at a wavelength that is shorter than the opticalstimulation wavelength.

Accordingly, in a preferred embodiment of the thirteenth aspect of theinvention, the wavelength of the optically stimulated luminescence, theintensity and duration of which is measured in step (d), is shorter thanthe at least one predetermined wavelength in step (c).

Accordingly, in a preferred embodiment of the fourteenth aspect of theinvention, the wavelength of the light emitted in step (d) is shorterthan wavelength of the stimulating light in step (c).

In one embodiment of any of the eleventh to the fourteenth aspects ofthe invention, prior to irradiation with ionizing radiation, thephosphor-doped fluoroperovskite compound is ground; the ground compoundis sintered at a temperature below the melting point of the compound;and the sintered phosphor-doped fluoroperovskite compound is cooled. Inone embodiment, the cooling of the sintered phosphor-dopedfluoroperovskite compound comprises quenching the compound.

In fifteenth aspect, the present invention also provides a dosimeter fordetecting ionizing radiation by TSL, comprising a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing; radiation, and releasing at least part ofthe stored energy upon heating, wherein the phosphor-dopedfluoroperovskite compound is as defined for any of the sixth to thetenth aspects of the invention.

In a sixteenth aspect, the present invention also provides a radiationstorage device comprising a phosphor-doped fluoroperovskite compound,capable of storing at least part of the energy of incident ionizingradiation, and releasing at least part of the stored energy uponheating, wherein the phosphor-doped fluoroperovskite compound is asdefined for any of the sixth to the tenth aspects of the invention.

In a seventeenth aspect, the present invention provides a method ofdetermining a dose of ionizing radiation comprising:

-   (a) providing a phosphor-doped fluoroperovskite compound, capable of    storing at least part of the energy of incident ionizing radiation,    and releasing at least part of the stored energy upon heating,    wherein the phosphor-doped fluoroperovskite compound is as defined    for any of the sixth to the tenth aspects of the invention;-   (b) irradiating the phosphor-doped fluoroperovskite compound with    ionizing radiation;-   (c) heating the irradiated phosphor-doped fluoroperovskite compound    in the dark;-   (d) measuring the intensity and duration of the luminescence from    the irradiated phosphor-doped fluoroperovskite compound at a    predetermined temperature or within a predetermined temperature    range or during a predetermined temperature ramp; and-   (e) relating, by calibration procedures, the intensity and duration    of the luminescence to the dose of ionizing radiation absorbed by    the phosphor-doped fluoroperovskite compound.

In an eighteenth aspect, the present invention provides a method forrecording and reproducing an ionizing radiation image comprising thesteps of:

-   (a) providing a phosphor-doped fluoroperovskite compound, capable of    storing at least part of the energy of incident ionizing radiation,    and releasing at least part of the stored energy upon heating,    wherein the phosphor-doped fluoroperovskite compound is as defined    for any of the sixth to the tenth aspects of the invention;-   (b) causing ionizing radiation to be incident upon the compound    through an object to be imaged, so that the compound stores energy    from the radiation;-   (c) exposing the compound to heat to release the stored energy as    emitted light;-   (d) detecting the emitted light for imaging.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isNa_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: Eu²⁺;Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Mn²⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isRb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Mn²⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isNa_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Pr³⁺ or Tb³⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, wherein the phosphor-doped fluoroperovskite compound isRb_(1−(x+x′))Na_(x)K_(x+)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; and the rareearth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Pr³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, wherein the phosphor-doped fluoroperovskitecompound is Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+),the dopant phosphor ion is Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+), and thedopant phosphor ion is Eu²⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, x, x′, y and z are all about 0.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound is NaMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: Eu²⁺; Pr³⁺; Tb³⁺; and Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃: Z^(d+), and the dopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃: Z^(d+), and the dopant phosphor ion is Mn²⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isRbMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺;and Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺ or Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is Mn²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Mn²⁺.

In a further preferred embodiment of any of the fifteenth to theeighteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.2% Eu²⁺;NaMgF₃:0.1% Pr³⁺; NaMgF₃:0.2% Tb³⁺; NaMgF₃:0.2% Mn²⁺; RbMgF₃:0.2% Eu²⁺;and RbMgF₃:0.2% Mn²⁺.

In a further preferred embodiment of any of the fifteenth to theeighteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is NaMgF₃:0.2% Eu²⁺.

In a further preferred embodiment of any of the fifteenth to theeighteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is RbMgF₃:0.2% Eu²⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound is NaMgF₃:Z^(d+), and the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, the phosphor-doped fluoroperovskite compound isRbMgF₃:Z^(d+), the dopant phosphor ion is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; and the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; andTb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Pr³⁺ or Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Pr³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis NaMgF₃:Z^(d+), and the dopant phosphor ion is Tb³⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis RbMgF₃:Z^(d+), and the dopant phosphor ion is Eu²⁺.

In a preferred embodiment of any of the fifteenth to the eighteenthaspects of the invention, the phosphor-doped fluoroperovskite compoundis selected from the group consisting of: NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; andRbMgF₃:Eu²⁺.

In a further preferred embodiment of any of the fifteenth to theeighteenth aspects of the invention, the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:0.1% Pr³⁺;NaMgF₃:0.2% Tb³⁺; and RbMgF₃:0.2% Eu²⁺.

In one embodiment of any of the fifteenth to the eighteenth aspects ofthe invention, prior to irradiation with ionizing radiation, thephosphor-doped fluoroperovskite compound is ground; the ground compoundis sintered at a temperature below the melting point of the compound;and the sintered phosphor-doped fluoroperovskite compound is cooled. Inone embodiment, the cooling of the sintered phosphor-dopedfluoroperovskite compound comprises quenching the compound.

In one embodiment of the seventeenth aspect, the method furthercomprises a step, before the step of heating the irradiatedphosphor-doped fluoroperovskite compound in the dark, of opticallystimulating the irradiated phosphor-doped fluoroperovskite compound witha predetermined intensity of light comprising at least one predeterminedwavelength and, optionally, measuring the intensity and duration of theoptically stimulated luminescence from the irradiated phosphor-dopedfluoroperovskite compound. In one embodiment, the optical stimulation isin a wavelength range from about 200 nm to about 1000 nm. In oneembodiment, the optical stimulation wavelength is from about 290 nm toabout 350 nm. In a preferred embodiment, the optical stimulationwavelength is from about 300 nm to about 1000 nm. In one embodiment, theoptical stimulation wavelength is about 470 nm. In a further preferredembodiment, the optical stimulation wavelength is in the near infrared(>700 nm). In a further preferred embodiment, the optical stimulationwavelength is about 875 nm.

In one embodiment of the eighteenth aspect, the method further comprisesa step, before the step of exposing the compound to heat to release thestored energy as emitted light, of optically stimulating the irradiatedphosphor-doped fluoroperovskite compound with a predetermined intensityof light comprising at least one predetermined wavelength and,optionally, measuring the intensity and duration of the opticallystimulated luminescence from the irradiated phosphor-dopedfluoroperovskite compound. In one embodiment, the optical stimulation isin a wavelength range from about 200 nm to about 1000 nm. In oneembodiment, the optical stimulation wavelength is from about 290 nm toabout 350 nm. In a preferred embodiment, the optical stimulationwavelength is from about 300 nm to about 1000 nm. In one embodiment, theoptical stimulation wavelength is about 470 nm. In a further preferredembodiment, the optical stimulation wavelength is in the near infrared(>700 nm). In a further preferred embodiment; the optical stimulationwavelength is about 875 nm.

In a nineteenth aspect, the present invention provides a method forpreparing a phosphor-doped fluoroperovskite compound, capable of storingat least part of the energy of incident ionizing radiation, andreleasing at least part of the stored energy upon optical stimulation orupon heating, wherein the phosphor-doped fluoroperovskite compound is asdefined for any of the first to the tenth aspectsof the invention, themethod comprising the steps:

-   (a) providing a mixture of precursor compounds;-   (b) heating the mixture to a temperature at or above the melting    point of the mixture to form a homogenous melt; and-   (c) cooling the melt to provide the phosphor-doped fluoroperovskite    compound.

In an alternative embodiment, step (b) comprises heating the mixture toa temperature below the melting point of the mixture and sintering themixture; and step (c) comprises cooling the sintered mixture to providethe phosphor-doped fluoroperovskite compound.

Preferably, one or both of steps (b) and (c) are carried out in anatmosphere having a low oxygen partial pressure. In one embodiment, theatmosphere having a low oxygen partial pressure is an argon atmosphere.In an alternative embodiment, the atmosphere is an argon-hydrogenatmosphere.

In one embodiment, the method further comprises the steps:

-   (d) grinding the phosphor-doped fluoroperovskite compound;-   (e) sintering the ground compound at a temperature below the melting    point of the compound; and-   (f) cooling the sintered phosphor-doped fluoroperovskite compound.

In one embodiment, step (c) comprises cooling the melt to a temperaturebelow the melting point of the phosphor-doped fluoroperovskite compoundand then quenching the compound. In an alternative embodiment, step (c)comprises quenching the molten phosphor-doped fluoroperovskite compound.

In one embodiment, step (f) comprises quenching the sinteredphosphor-doped fluoroperovskite compound.

In a twentieth aspect, the present invention provides a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation or upon heating, preparedsubstantially according to the method of the nineteenth aspect of theinvention.

In other aspects, the present invention provides dosimeters fordetecting ionizing radiation by OSL and/or by TSL, radiation storagedevices, methods of determining a dose of ionizing radiation and methodsfor recording and reproducing an ionizing radiation image; all utilizinga phosphor-doped fluoroperovskite compound, capable of storing at leastpart of the energy of incident ionizing radiation, and releasing atleast part of the stored energy upon optical stimulation or uponheating, wherein the compound is prepared substantially according to themethod of the nineteenth aspect of the invention.

Specific and preferred embodiments of these other aspects are as recitedabove for any of the eleventh to the eighteenth aspects of theinvention.

This invention may also be said broadly to consist in the parts,elements and features referred to or indicated in the specification ofthe application, individually or collectively, and any or allcombinations of any two or more said parts, elements or features, andwhere specific integers are mentioned herein which have knownequivalents in the art to which this invention relates, such knownequivalents are deemed to be incorporated herein as if individually setforth.

As used herein with respect to the fluoroperovskite compound, the term“phosphor-doped” means that up to a few mole percent of the ions in thecompound have been replaced with a different ion, which results in newproperties. For example, in the fluoroperovskite compounds described inthe examples, NaMgF₃:0.2% Eu²⁺ means that 0.2% of the Mg²⁺ ions arereplaced with Eu²⁺ ions.

In one embodiment, the mole percent of dopant phosphor ions replacingthe Mg²⁺ ions and Zn²⁺ ions, if present, in the fluoroperovskitecompound is between 0.001% and 10%. In a preferred embodiment, the molepercent of dopant phosphor ions is between 0.01% and 2%, more preferablybetween 0.01% and 1%, more preferably between 0.1% and 0.5%.

As used herein the term “quenching” means the rapid cooling of thephosphor-doped fluoroperovskite compound to a lower temperature. Thequenching may proceed, for example, by contact with liquids or gaseswhich are cooler than the molten or solid compound. Alternatively, themolten compound can be poured onto a colder metal surface or into a moldat the lower temperature to form the solid compound.

As used herein the term “storing” with respect to radiation means that,following irradiation of the phosphor-doped fluoroperovskite compound,part of the energy is stored in the form of trapped electrons and holes.Subsequent exposure of the compound to stimulating light or heat leadsto detrapping of the trapped electrons and holes followed by energytransfer to the dopant phosphor ion and then emission of light from thephosphor ion.

The term “comprising” as used, in this specification means “consistingat least in part of”. When interpreting each statement in this;specification that includes the term “comprising”, features other thanthat or those prefaced by the term may also be present. Related termssuch as “comprise” and “comprises” are to be interpreted in the samemanner.

It is intended that reference to a range of numbers disclosed herein(for example, 1 to 10) also incorporates reference to all rationalnumbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5,7, 8, 9 and 10) and also any range of rational numbers within that range(for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, allsub-ranges of all ranges expressly disclosed herein are hereby expresslydisclosed. These are only examples of what is specifically intended andall possible combinations of numerical values between the lowest valueand the highest value enumerated are to be considered to be expresslystated in this application in a similar manner.

Although the present invention is broadly as defined above, thosepersons skilled in the art will appreciate that the invention is notlimited thereto and that the invention also includes embodiments ofwhich the following description gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the Figures inwhich:

FIG. 1 shows the room temperature OSL emission from as-made NaMgF₃:0.2%Eu²⁺, NaMgF₃:0.1% Pr³⁺, NaMg₃:0.2% Tb³⁺, and NaMgF₃:0.2% Mn²⁺;

FIG. 2 (a) shows the TSL after X-ray irradiation of as-made NaMgF₃:0.2%Eu²⁺ and (b) shows the TSL after X-ray irradiation of a sintered andliquid nitrogen quenched NaMgF₃:0.2% Eu²⁺ sample;

FIG. 3 shows the TSL after β irradiation of as-made NaMgF₃:0.02% Mn²⁺;

FIG. 4 shows the integrated TSL intensity of as-made NaMgF₃:0.02% Mn²⁺as a function of X-ray dose;

FIG. 5 shows the decay curve of the room temperature OSL from a sinteredand liquid nitrogen quenched NaMgF₃:0.2% Eu²⁺ sample, and the insetshows the dark decay;

FIG. 6 shows the room temperature OSL emission from KMgF₃:0.2% Eu²⁺;

FIG. 7 is a plot of the time integrated room temperature OSL intensityfrom KMgF₃:0.2% Eu²⁺ against the β radiation dose;

FIG. 8 shows the room temperature OSL emission after X-ray irradiationof RbMgF₃:0.2% Eu²⁺ and RbMgF₃:0.2% Ce³⁺;

FIG. 9 shows the room temperature OSL decay curves after β irradiationfor RbMgF₃:0.2% Eu²⁺ during continual stimulation with an infrared LEDor a blue LED;

FIG. 10 shows the room temperature OSL decay curve for RbMgF₃:0.2% Eu²⁺after γ-irradiation and immediate stimulation with light above 435 nm or715 nm and with a five day delay between irradiation and stimulation;

FIG. 11 shows the TSL from RbMgF₃:0.2% Eu²⁺;

FIG. 12 shows the TSL from RbMgF₃:0.2% Eu²⁺ after X-ray irradiation bothwith and without illumination with an infrared LED;

FIG. 13 shows the room temperature OSL decay curves for NaMgF₃:0.2% Eu²⁺after β irradiation and stimulation with an infrared LED or a blue LED;

FIG. 14 shows the room temperature OSL decay curve for NaMgF₃:0.2% Eu²⁺after β irradiation and stimulation with a blue LED;

FIG. 15 is a plot of the time integrated room temperature OSL intensityafter X-ray irradiation of a sintered and liquid nitrogen quenchedNaMgF₃:0.2% Eu²⁺ sample and stimulation with a blue LED, and the insetshows the time integrated OSL intensity for high β radiation doses;

FIG. 16 shows the room temperature OSL decay curve for NaMgF₃:0.2% Eu²⁺and Al₂O₃:C after X-ray irradiation and during constant stimulation; and

FIG. 17 shows the TSL, after a brief exposure to X-rays, from as-madeand sintered RbMgF₃ doped with nominal Mn²⁺ concentrations of: (a) 5%;(b) 2%; (c) 0.7%; (d) 0.2%; (e) 0.05%; and (f) 0%.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to fluoroperovskite compounds activated bya phosphor ion dopant that display OSL or TSL after exposure to ionizingradiation. Such compounds are particularly suitable for the measurementof ionizing radiation dosage by OSL and TSL, and can also be used as aphosphor for radiation imaging.

The present invention also relates to radiation dosimeters, imagingplates and other radiation monitoring devices based on thefluoroperovskite compounds.

Irradiation of the phosphor-doped fluoroperovskite compound leads to theexcitation of electrons and holes that become trapped in the compound.The concentration of the trapped electrons and holes is related to theradiation dose and the spatial distribution of trapped electrons andholes can be used to generate a two-dimensional dose distributionprofile. The spatial distribution and concentration of trapped electronsand holes can also represent a latent X-ray image for X-ray imaging orradiation dose distribution applications.

The stored dose or image information can be read out promptly or at alater time by conventional OSL or TSL methods.

For OSL read-out, the irradiated phosphor-doped fluoroperovskitecompound is exposed to stimulating light, which leads to therecombination of the trapped electrons and holes and the emission of thelight. The emitted light is known as OSL emission. The emitted light canbe recorded as a function of time during continual stimulation, and thetime integrated OSL emission intensity will be proportional to theradiation dose. It is also possible to stimulate the sample with weakstimulating light for a short period and record the OSL emission. Theintensity can be related to the radiation dose, and this method enablesthe dose information to be periodically monitored.

For radiation imaging applications, in which the phosphor-dopedfluoroperovskite compound is typically formed into a plate using methodsknown to those skilled in the art, the image can be read-out via ascanning stimulating beam or by stimulating the entire plate.

For TSL read-out, the irradiated phosphor-doped fluoroperovskitecompound is heated at a rate that is typically between 0.01 K/s and 25K/s. In one embodiment, the heating rate is about 1 K/s.

Heating leads to thermal excitation of the trapped carriers andelectron-hole recombination followed by the emission of TSL light. Theintensity and temperature dependence of the TSL emission can be relatedto the radiation dose.

The phosphor-doped fluoroperovskite compounds for OSL applications areselected from:

Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+) whereinZ^(d+) is the dopant phosphor ion and is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; andTb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 andz≦0.3;

K_(1−(x+x′))Na_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+) whereinZ^(d+) is the dopant phosphor ion and is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; andTb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 andz≦0.3;

Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+) whereinZ^(d+) is the dopant phosphor ion and is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; andCr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; andTb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 andz≦0.3;

and mixtures of any two or more thereof.

The phosphor-doped fluoroperovskite compounds for TSL applications areselected from:

Na_(1−(x+x′))K_(x)Rb_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z) wherein Z^(d+) isthe dopant phosphor ion and is selected from the group consisting of:the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺;In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 and z≦0.3;

Rb_(1−(x+x′))Na_(x)K_(x′)Mg_(1−y)Zn_(y)F_(3−z)Cl_(z):Z^(d+) whereinZ^(d+) is the dopant phosphor ion and is selected from the groupconsisting of: the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺;and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; andTb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and wherein (x+x′)≦0.1, y≦0.1 andz≦0.3;

and mixtures of any two or more thereof.

The phosphor-doped fluoroperovskite compounds useful in the inventionare sensitive to X-rays, gamma-rays, beta particles, alpha particles andother forms of ionizing radiation.

The phosphor-doped fluoroperovskite compounds useful in the inventionmay be prepared from suitable precursor compounds by methods known tothose persons skilled in the art.

Suitable precursor compounds include: the alkali metal fluorides: NaF;KF and RbF; MgF₂ and ZnF₂; and various dopant phosphor ion compounds.

A preferred method of preparation involves placing a mixture of theprecursor compounds in a crucible. The mixture is then heated to form ahomogeneous melt. Typically, the mixture of precursor compounds isheated to a temperature that is about 50° C. above the melting point ofthe mixture. However, lower or higher temperatures—as high as about1200° C.—may also be used. The maximum temperature for a particularmixture will be determined by the vapor pressures of the individualprecursor compounds.

Typically, the mixture is heated in an atmosphere having a low oxygenpartial pressure. In a preferred embodiment, the mixture is heated inargon, but other gases and mixtures may be used including, but notlimited to: dry nitrogen; argon-hydrogen; and nitrogen-hydrogen.

The mixture is held at or above the melting temperature for a period oftime, typically at least 20 minutes. The temperature is then ramped downto room temperature. The resultant material is polycrystalline.

In an alternative embodiment, the phosphor-doped fluoroperovskitecompound may be prepared by heating a mixture of the precursor compoundsto a temperature which is below the melting point and sintering themixture to form the compound.

In other embodiments, the phosphor-doped fluoroperovskite compound maybe prepared by known methods of single crystallite synthesis—forexample, the Bridgman method or the Czochralski process.

Generally, the precursor dopant phosphor ion compound will be selectedsuch that the dopant phosphor ion has the desired valency. In someembodiments, the precursor compound will include dopant phosphor ionshaving a higher valency than that desired for incorporation in thephosphor-doped fluoroperovskite compound. For example, a Eu³⁺ precursor(such as Eu₂O₃) may be used to prepare compounds in which the desireddopant phosphor ion is Eu²⁺. In such embodiments, the mixture ofprecursor compounds may be heated in a reducing atmosphere, such as 95%argon-5% hydrogen, to ensure that the dopant phosphor ions are reducedto the desired valency.

The resultant phosphor-doped fluoroperovskite compound may be ground andthen sintered at temperatures below the melting point and then quenchedfrom temperatures as high as 1100° C. to optimize the response of thecompound to ionizing radiation. This quenching procedure may also beapplied to the as-made phosphor-doped fluoroperovskite compound, withoutthe intermediate grinding and sintering.

In a preferred embodiment, the temperature of the phosphor-dopedfluoroperovskite compound before quenching is less than about 200° C.below the melting point of the compound, and preferably close to themelting point.

Without wishing to be bound by theory, the grinding and sinteringprocess is thought to lead to diffusivity of the fluorine vacancies andother defects, and to increase their concentration, in thephosphor-doped fluoroperovskite compound structure. Rapid quenching ofthe compound “freezes” these vacancies and defects, whereas slow coolingmay lead to a decrease in the trap distribution, depth and type.

The phosphor-doped fluoroperovskite compound can also be ground into afine powder and dispersed in a polymer to enable the formation ofarbitrary shapes, including panels, and to ensure long term materialstability.

The phosphor-doped fluoroperovskite compound useful in the presentinvention may be used to produce an ionizing radiation imaging device bycombining the compound with a source of ionizing radiation, to irradiatethe compound. Subsequent illumination with stimulating light, orheating, can be used to cause luminescence of the compound to create animage using conventional techniques.

The following examples are provided to illustrate the present inventionand in no way limit the scope thereof.

EXAMPLES Example 1

Four NaMgF₃ samples, doped with 0.2% Eu²⁺, 0.2% Mn²⁺, 0.1% Pr³⁺ and 0.2%Tb³⁺, respectively, were prepared. The samples were prepared fromstoichiometric quantities of NaF and MgF₂ with appropriateconcentrations of EuF₃, MnF₂, PrF₃ or TbF₃. The precursors were placedin a vitreous carbon crucible and heated in an argon atmosphere to 1070°C. That temperature was held for 120 minutes. The temperature was thencooled to 1030° C. at a rate of 1 K/min, then to 1010° C. at 2 K/hour.This was followed by furnace cooling to room temperature.

The room temperature OSL emission spectra after exposure to X-rays areshown in FIG. 1 for NaMgF₃:0.2% Eu²⁺ (solid curve, stimulated at 500nm), NaMgF₃:0.1% Pr³⁺ (dashed curve, stimulated at 800 nm), NaMgF₃:0.2%Tb³⁺ (dotted curve, stimulated at 470 nm), and NaMgF₃:0.2% Mn²⁺(dot-dash curve, stimulated 375 nm). The stimulation wavelength islonger than the emission wavelength for the samples doped with Eu²⁺,Pr³⁺ and Tb²⁺. This is advantageous because excitation at wavelengthsshorter than the emission wavelength can lead to photoluminescence fromthe fluorescent ion excited states. This will limit the minimumdetectable dose. The OSL can be bleached by stimulating in the OSLexcitation band and the time integrated OSL emission intensity isproportional to the radiation dose.

FIG. 2( a) is a plot of the TSL glow curve from the Eu²⁺ doped sample ata heating rate of 1 K/s and after X-ray irradiation. FIG. 2( a) showsthat this compound can also be used to measure the radiation dose byTSL.

Example 2

A sample of NaMgF₃:0.02% Mn²⁺ was prepared using the procedure inExample 1. The TSL data, at a heating rate of 1 K/s and after βirradiation, are plotted in FIG. 3. There is one main high temperaturetrap, which is a desirable property for a TSL dosimeter.

The TSL dose response to X-ray irradiation for another NaMgF₃:0.02% Mn²⁺sample is shown in FIG. 4. The dose response to X-rays is linear up to300 Gy and increases for doses exceeding 1 kGy. This is a desirableproperty for a TSL dosimeter and the high dose response exceeds that ofcommercial TSL materials.

Example 3

A sample of NaMgF₃:0.2% Eu²⁺, prepared using the procedure in Example 1,was ground, pressed into pellets and sintered at 900° C. in an airatmosphere for 2 hours. The sample was then quenched in liquid nitrogen.

The resulting OSL excitation and emission spectra after exposure toionizing radiation were similar to those observed for the as-madesample.

The OSL can be bleached by stimulating with wavelengths ranging from theinfrared to approximately 300 nm, and the time integrated OSL emissionis proportional to the radiation dose. An example of the radiation doseread-out after 0.1 Gy β irradiation is shown in FIG. 5. The OSL wasstimulated by a blue LED centered at 470 nm. The emitted light waspassed through a Hoya U-340 UV bandpass glass filter and detected with aphotomultiplier tube. It can be seen that there is rapid bleaching,which a desirable characteristic for OSL dosimeters.

The dark decay is shown in the inset to FIG. 5, where the integrated OSLis plotted for different times after the radiation dose. There is asmall dark decay for times less than 24 hours and the dose informationis stable after 1 day. The observed dark decay may be attributable tothe specific sintering and annealing process used for this sample anddoes not reflect the dark decay observed for as-made material.

The TSL data at a heating rate of 1 K/s and after X-ray irradiation areplotted in FIG. 2( b). Compared to the data for as-made NaMgF₃:0.2%Eu²⁺, which are shown in FIG. 2( a), the TSL data also show asignificant reduction for temperatures below 100° C. It should be notedthat it is these shallow traps that lead to the afterglow and initialdecrease in the dark decay in the as-made samples. It is also apparentthat sintering and quenching lead to a significant decrease in the TSLglow curves for temperatures above 300° C. This indicates that sinteringand quenching leads to a reduction in the density of deep traps. A lowconcentration of deep traps is desirable for OSL dosimeters because deeptraps require high read-out intensities.

Example 4

KMgF₃ doped with 0.2% Eu²⁺ was prepared from stoichiometric quantitiesof KF and MgF₂ with an appropriate concentration of EuF₃. The precursorswere placed in a platinum crucible and heated in an argon atmosphere to1100° C. That temperature was held for 120 minutes. The temperature wasthen cooled to 1080° C. at a rate of 1 K/min, then to 1060° C. at 2K/hour. This was followed by furnace cooling to room temperature.

The room temperature OSL emission spectra, after X-ray irradiation andstimulation at 450 nm, are shown in FIG. 6. The dose response is shownFIG. 7, which is a plot of the time integrated OSL intensity against theradiation dose. The response is linear up to kGy, which is desirable fora OSL dosimeter.

Example 5

RbMgF₃ doped with 0.2% Eu²⁺ and 0.2% Ce³⁺ were prepared fromstoichiometric quantities of RbF and MgF₂ with appropriateconcentrations of EuF₃ or CeF₃. The precursors were placed in a vitreouscarbon crucible and heated in an argon atmosphere to 970° C. Thattemperature was held for 120 minutes. The temperature was then cooled to920° C. at a rate of 1 K/min, then to 900° C. at 2 K/hour. This wasfollowed by furnace cooling to room temperature.

The room temperature OSL emission spectra after X-ray irradiation areshown in FIG. 8 for RbMgF₃:0.2% Eu²⁺ (solid curve, stimulated at 580 nm)and RbMgF₃:0.2% Ce³⁺ (dashed curve, stimulated at 450 nm).

The dose read-out can be obtained by continual stimulation and detectionof the emitted light. This is shown in FIG. 9 where the OSL emissionintensity from RbMgF₃:0.2% Eu²⁺ is plotted during continual stimulationwith an infrared LED centered at 875 nm (IRSL, solid curve) or a blueLED centered at 470 nm (Blue SL, dashed curve) after 0.1Gy irradiation.

FIG. 10 shows the dose read-out for RbMgF₃:0.2% Eu²⁺ after irradiationwith a γ-ray source (60 keV) to a dose of approximately 400 mGy. FIG. 10shows the infrared stimulated luminescence (IRSL) decay when stimulatingwith light above 715 nm immediately after irradiation and with a fiveday delay between irradiation and stimulation. FIG. 10 also shows theOSL decay when stimulating with light above 435 nm immediately afterirradiation and with a five day delay between irradiation andstimulation. These data show that partial dose information can beobtained by stimulating with light from the blue to the infrared. It isalso possible to read-out the dose information with wavelengths as lowas 300 nm, provided that suitable emission and detection optical filtersare used.

The radiation dose can also be obtained by TSL. This is shown in FIG.11, which is a plot of the TSL data for RbMgF₃:0:2% EU²⁺, after X-rayirradiation with a temperature ramp of 1 K/s.

FIG. 12 is a comparison of the TSL data for RbMgF₃:0.2% Eu²⁺ after X-rayirradiation (solid curve) and the TSL data after a similar X-ray doseand illumination with an infrared LED centered at 875 nm (dashed curve).This comparison shows that the material can be used as a TSL dosimeterand that infrared stimulation depopulates the traps associated with thelow temperature peaks that are also responsible for the initial darkdecay.

The radiation sensitivity of RbMgF₃:0.2% Eu²⁺ was compared with that ofa commercial BaFBr:Eu²⁺ storage phosphor plate (AGFA MD30). Samples ofapproximately the same area (2.1×4.5 mm²) and thickness (0.7 mm) wereprepared. These dimensions were chosen to match the spot size of theexcitation light of a Hitachi fluorescence spectrometer with a band passof 20 nm. The samples were then subjected to a dose of 5.4 mGy byirradiation with an ²⁴¹Am source for 5 minutes at a distance ofapproximately 2 cm. The OSL data were obtained using 633 nm excitationlight with an OG590 filter and detecting at 395 nm with BG18 and UG5filters for the imaging plate sample (for which the OSL emission occursat 395 nm), and 0th order light from the excitation monochromator with aGG435 filter and detecting at 360 nm with BG18, UG11 and UG1 filters forthe RbMgF₃:0.2% Eu²⁺ sample. The emission spectra were not corrected forthe excitation intensity, so the detected signal was a measure of thetotal OSL yield. The signals, integrated over the first 100 s (more than90% of the signal was depleted in all cases), were measured relative tothe value obtained for the imaging plate. The RbMgF₃:0.2% Eu²⁺ samplewas found to have a relative conversion efficiency of 32%.

Example 6

A sample of NaMgF₃:0.2% Eu²⁺ was prepared using the procedure inExample 1. The sample was β-irradiated (100 mGy) and the OSL emissionrecorded as a function of time during continual OSL stimulation with aninfrared LED centered at 875 nm. The irradiation was repeated and theOSL emission recorded as a function of time during continual OSLstimulation with a blue LED centered at 470 nm. The room temperature OSLdecay curves are shown in FIG. 13, which shows that a wide range ofwavelengths can be used to read-out part or all of the dose information.

The OSL decay from a 28 mg sample after 3 μGy β irradiation is plottedin FIG. 14, which shows the OSL emission intensity as a function of timeduring continual stimulation with a blue LED centered at 470 nm. Itshows the sensitivity of this material to ionizing radiation.

The time integrated OSL signal is proportional to the radiation dose.FIG. 15 is a plot of the time integrated room temperature OSL intensityagainst the radiation dose after X-ray irradiation. FIG. 15 shows thatthe OSL response is linear for relatively low doses. The inset shows thedose response to higher X-ray doses. It shows that the dose response islinear to 100 Gy and that there is still a dose response to 1 kGy. Thisis in contrast to Al₂O₃:C where the dose response saturates atapproximately 100 Gy. A wide range of dose response and a high doselimit is very desirable in OSL dosimeters, which can also be used forradiation therapy as well as non-destructive testing. There isnegligible fading after 24 hours.

FIG. 16 compares the OSL emission intensity as a function of time forNaMgF₃:0.2% Eu²⁺ (solid curve) and a transparent Al₂O₃:C dosimetersample obtained from Landauer (dashed curve). A direct comparison withthe industry standard OSL material Al₂O₃:C is not straightforwardbecause of the differences in the stimulation and emissioncharacteristics. The main emission of Al₂O₃:C occurs around 420 nm, andthe stimulation maximum appears in the same wavelength region, butextends to red and infrared wavelengths.

For comparison, rectangular samples of 2.5×4.5 mm² and 0.5 mm thicknesswere cut and irradiated with X-rays to approximately 10 Gy. OSL read-outwas performed in a Hitachi fluorescence spectrometer. The beam widthusing a stimulation band pass was wide enough to cover the total sampleareas, thus providing complete dose read-out. For Al₂O₃:C, theexcitation monochromator was set to 560 nm, and the emissionmonochromator to 420 nm. Additional wavelength separation was providedby inserting a GG495 filter in front of the excitation aperture and aBG3 filter in front of the detection aperture. NaMgF₃:0.2% Eu²⁺ was readout with 425 nm stimulation, 360 nm emission and GG400 and UG11 filters,respectively.

The stimulation efficiency in this setup was much higher for NaMgF₃:0.2%Eu²⁺. While the initial OSL intensity of NaMgF₃:0.2% Eu²⁺ isapproximately a factor of 4 higher than that of Al₂O₃:C, the timeintegrated intensity is approximately a factor of 4 smaller. Withouttaking into account the detector characteristics, these values are notvery significant, but show that the sensitivity of both materials is inthe same order of magnitude.

Example 7

RbMgF₃:Mn²⁺ doped with different Concentrations of Mn²⁺ were preparedfrom stoichiometric quantities of RbF and MgF₂ with appropriateconcentrations of MnF₂. The precursors were placed in a vitreous carboncrucible and heated in an argon atmosphere to 970° C. That temperaturewas held for 120 minutes. The temperature was then cooled to 920° C. ata rate of 1 K/min, then to 900° C. at 2 K/hour. This was followed byfurnace cooling to room temperature.

Sintered pellets were prepared by grinding part of each sample andpressing into a disc using a die. They were then sintered at 880° C. for3 hours in argon and then furnace cooled to room temperature.

The TSL data for the as-made (solid curves) and sintered (dashed curves)samples after a short exposure to X-rays are shown in FIG. 17. Thenominal Mn²⁺ nominal concentrations were: (a) 5%; (b) 2%; (c) 0.7%; (d)0.2%; (e) 0.05%; and (f) 0%. The ramp rate was 1 K/s. These data showthat sintering can result in a reduction in the relative intensity ofthe low temperature peaks, which is advantageous for a TSL dosimeter.

Conclusions

The fluoroperovskite compounds described in these Examples have a numberof advantages over materials currently used in dosimetry applicationsand as storage phosphors. For example, RbMgF₃:Eu²⁺ has a higher OSLsensitivity to ionizing radiation than Al₂O₃:C and it is slightly lessthan that found for a commercial X-ray storage phosphor plate comprisingBaFBr:Eu²⁺. However, unlike the imaging plate, the dose information doesnot degrade, even for times as long at 24 hours.

Infrared stimulation of RbMgF₃:Eu²⁺ ensures that the exciting light isfar removed from the emitted light and, hence, the minimal detectabledose is lower because of the reduced leakage into the detector from thestimulating light. If the detector is a photomultiplier detector withphoton counting, then infrared stimulation enables the OSL emission tobe detected without the need for optical filters. This is because asufficiently long infrared stimulation wavelength, which is not detectedby the photomultiplier, can be selected.

KMgF₃:Eu²⁺ has a linear dose response to nearly 1000 Gy. This issignificantly greater than the linear dose range reported for the OSLdosimeter material Al₂O₃:C or even for TSL dosimeters.

NaMgF₃:Mn²⁺ has a higher TSL sensitivity and higher maximum detectabledose limit than TLD-100 (LiF:Mg,Ti). The effective afoftiic number ofNaMgF₃ is lower than that of Al₂O₃, which is advantageous for personaldosimetry.

The conversion efficiency of NaMgF₃:Eu²⁺ is slightly less than that ofAl₂O₃:C but NaMgF₃:Eu²⁺ has a higher maximum recordable dose limit.Furthermore, most of the dose information can be read out via infraredstimulation and the peak OSL emission wavelength matches that ofphotomultiplier tube detectors. Advantageously, this enables highlysensitive dosimeter measurements using infrared stimulation above 650 nmwithout requiring optical filters as well as photon counting using aphotomultiplier to detect the OSL emission at the peak of thephotomultiplier tube sensitivity.

INDUSTRIAL APPLICATION

The present invention provides fluoroperovskite compounds that can beused in, for example, OSL and TSL personal dosimeters to measure thebiological exposure to harmful ionizing radiation, and in medicalapplications to measure the dose during radiation therapy.

The fluoroperovskite compounds may also be used in the manufacture ofradiation imaging plates for X-rays, gamma-rays and thermal neutrons formedical and non-destructive testing applications where a slow dark decayof the image is required. Such imaging plates may be used, for example,in medical X-ray imaging in remote locations where the image is read outat a central location, and in gamma-ray or X-ray imaging of criticalvalves or pipes in remote locations where the read-out is done up to twoor more weeks later.

It is not the intention to limit the scope of the invention to theabove-mentioned examples only. As would be appreciated by a skilledperson in the art, many variations are possible without departing fromthe scope of the invention as set out in the accompanying claims.

1-133. (canceled)
 134. A phosphor-doped fluoroperovskite compound,capable of storing at least part of the energy of incident ionizingradiation, and releasing at least part of the stored energy upon opticalstimulation, wherein the phosphor-doped fluoroperovskite compound isselected from the group consisting of: NaMgF₃:Z^(d+) wherein Z^(d+) isthe dopant phosphor ion and is selected from the group consisting of:the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺;In⁺; Ga⁺; and Pb²⁺; KMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphorion and is selected from the group consisting of: the transition metalions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions:Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; andRbMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is selectedfrom the group consisting of: the transition metal ions: Cu⁺; Ag⁺; Mn³⁺;Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺;Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; and mixtures of any two ormore thereof.
 135. The phosphor-doped fluoroperovskite compound, asclaimed in claim 134, selected from the group consisting of:NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺;RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.
 136. The phosphor-doped fluoroperovskitecompound, as claimed in claim 134, wherein the mole percent of dopantphosphor ions replacing the Mg²⁺ ions in the fluoroperovskite compoundis between 0.001% and 10%, between 0.01% and 2%, between 0.01% and 1%,or between 0.1% and 0.5%.
 137. A phosphor-doped fluoroperovskitecompound, capable of storing at least part of the energy of incidentionizing radiation, and releasing at least part of the stored energyupon heating, wherein the phosphor-doped fluoroperovskite compound isselected from the group consisting of: NaMgF₃: Z^(d+) wherein Z^(d+) isthe dopant phosphor ion and is selected from the group consisting of:the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺;In⁺; Ga⁺; and Pb²⁺; and RbMgF₃:Z^(d+) wherein Z^(d+) is the dopantphosphor ion and is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³t; Mn⁴⁺; and Cr³⁺; the rareearth metal ions: En²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺;Ga⁺; and Pb²⁺; and mixtures of any two or more thereof.
 138. Thephosphor-doped fluoroperovskite compound, as claimed in claim 137,selected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Mn²⁺.
 139. Thephosphor-doped fluoroperovskite compound, as claimed in claim 137,wherein the mole percent of dopant phosphor ions replacing the Mg²⁺ ionsin the fluoroperovskite compound is between 0.001% and 10%, between0.01% and 2%, between 0.01% and 1%, or between 0.1% and 0.5%.
 140. Adosimeter for detecting ionizing radiation by OSL, comprising aphosphor-doped fluoroperovskite compound, capable of storing at leastpart of the energy of incident ionizing radiation, and releasing atleast part of the stored energy upon optical stimulation, as claimed inclaim
 134. 141. A radiation storage device comprising a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, as claimed in claim 134.142. The dosimeter as claimed in claim 140 wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺;RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.
 143. The radiation storage device asclaimed in claim 141, wherein the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:Eu²⁺;NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; andRbMgF₃:Ce³⁺.
 144. A dosimeter for detecting ionizing radiation by TSL,comprising a phosphor-doped fluoroperovskite compound, capable ofstoring at least part of the energy of incident ionizing radiation, andreleasing at least part of the stored energy upon heating, as claimed inclaim
 137. 145. The radiation storage device comPrgin_(g) aphosphor-doped fluoroperovskite compound, capable of storing at leastpart of the energy of incident ionizing radiation, and releasing atleast part of the stored energy upon heating, as claimed in claim 137.146. The dosimeter as claimed in claim 144 wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; RbMgF₃:Eu²⁺; andRbMgF₃:Mn²⁺.
 147. The radiation storage device as claimed in claim 145,wherein the phosphor-doped fluoroperovskite compound is selected fromthe group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺;NaMgF₃:Mn²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Mn²⁺.
 148. A method of determininga dose of ionizing radiation comprising: (a) providing a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon optical stimulation, as claimed in claim 134; (b)irradiating the phosphor-doped fluoroperovskite compound with ionizingradiation; (c) optically stimulating the irradiated phosphor-dopedfluoroperovskite compound with a predetermined intensity of lightcomprising at least one predetermined wavelength; (d) measuring theintensity and duration of the optically stimulated luminescence from theirradiated phosphor-doped fluoroperovskite compound; and (e) relating,by calibration procedures, the intensity and duration of the opticallystimulated luminescence to the dose of ionizing radiation absorbed bythe phosphor-doped fluoroperovskite compound.
 149. A method forrecording and reproducing an ionizing radiation image comprising thesteps of: (a) providing a phosphor-doped fluoroperovskite compound,capable of storing at least part of the energy of incident ionizingradiation, and releasing at least part of the stored energy upon opticalstimulation, as claimed in claim 134; (b) causing ionizing radiation tobe incident upon the compound through an object to be imaged, so thatthe compound stores energy from the radiation; (c) exposing the compoundto stimulating light to release the stored energy as emitted light; (d)detecting the emitted light for imaging.
 150. The method as claimed inclaim 148; wherein the phosphor-doped fluoroperovskite compound isselected from the group consisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺;NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺. 151.The method as claimed in claim 149, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺,RbMgF₃:Eu²⁺; and RbMgF₃:Ce³⁺.
 152. A method of determining a dose ofionizing radiation comprising: (a) providing a phosphor-dopedfluoroperovskite compound, capable of storing at least part of theenergy of incident ionizing radiation, and releasing at least part ofthe stored energy upon heating, as claimed in claim 137; (b) irradiatingthe phosphor-doped fluoroperovskite compound with ionizing radiation;(c) heating the irradiated phosphor-doped fluoroperovskite compound inthe dark; (d) measuring the intensity and duration of the luminescencefrom the irradiated phosphor-doped fluoroperovskite compound at apredetermined temperature or within a predetermined temperature range orduring a predetermined temperature ramp; and (e) relating, bycalibration procedures, the intensity and duration of the luminescenceto the dose of ionizing radiation absorbed by the phosphor-dopedfluoroperovskite compound.
 153. A method for recording and reproducingan ionizing radiation image comprising the steps of: (a) providing aphosphor-doped fluoroperovskite compound, capable of storing at leastpart of the energy of incident ionizing radiation, and releasing atleast part of the stored energy upon heating, as claimed in claim 137;(b) causing ionizing radiation to be incident upon the compound throughan object to be imaged, so that the compound stores energy from theradiation; (c) exposing the compound to heat to release the storedenergy as emitted light; (d) detecting the emitted light for imaging.154. The method as claimed in claim 152, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; RbMgF₃:Eu²⁺; andRbMgF₃:Mn²⁺.
 155. The method as claimed in claim 153, wherein thephosphor-doped fluoroperovskite compound is selected from the groupconsisting of: NaMgF₃:Eu²⁺; NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺;RbMgF₃:Eu²⁺; and RbMgF₃:Mn²⁺.
 156. A method for preparing aphosphor-doped fluoroperovskite compound, wherein the phosphor-dopedfluoroperovskite compound is selected from the group consisting of:NaMgF₃:Z^(d+) wherein Z^(d+) is the dopant phosphor ion and is selectedfrom the group consisting of: the transition Metal ions: Cu⁺; Ag⁺; Mn²⁺;Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺;Gd³⁺; and Tb³⁺; and Tl⁺; In⁺; Ga⁺; and Pb²⁺; KMgF₃:Z^(d+) wherein Z^(d+)is the dopant phosphor ion and is selected from the group consisting of:the transition metal ions: Cu⁺; Ag⁺; Mn²⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; therare earth metal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Gd³⁺; and Tb³⁺; and Tl⁺;In⁺; Ga⁺; and Pb²⁺; and RbMgF₃:Z^(d+) wherein Z^(d+) is the dopantphosphor ion and is selected from the group consisting of: thetransition metal ions: Cu⁺; Ag⁺; Mn³⁺; Mn⁴⁺; and Cr³⁺; the rare earthmetal ions: Eu²⁺; Sm²⁺; Sm³⁺; Pr³⁺; Ce³⁺; Gd³⁺; and Tb³⁺; and Tl⁺; In⁺;Ga⁺; and Pb²⁺; and mixtures of any two or more thereof, and wherein thephosphor-doped fluoroperovskite compound is capable of storing at leastpart of the energy of incident ionizing radiation, and releasing atleast part of the stored energy upon optical stimulation or uponheating, the method comprising the steps: (a) providing a mixture ofprecursor compounds; (b) heating the mixture to a temperature at orabove the melting point of the mixture to form a homogenous melt, orheating the mixture to a temperature' below the melting point of themixture and sintering the mixture; and (c) cooling the melt to providethe phosphor-doped fluoroperovskite compound.
 157. The method, asclaimed in claim 156, wherein step (c) comprises cooling the melt to atemperature below the melting point of the phosphor-dopedfluoroperovskite compound and then quenching the compound.
 158. Themethod, as claimed in claim 156, wherein step (c) comprises quenchingthe melt or quenching the sintered mixture.
 159. The method, as claimedin claim 156, wherein one or both of steps (b) and (c) are carried outin an atmosphere having a low oxygen partial pressure.
 160. The method,as claimed in claim 156, further comprising the steps: (d) grinding thephosphor-doped fluoroperovskite compound; (e) sintering the groundcompound at a temperature below the melting point of the compound; andcooling the sintered phosphor-doped fluoroperovskite compound.
 161. Themethod as claimed in claim 160, wherein step (f) comprises quenching thesintered phosphor-doped fluoroperovskite compound.
 162. The method asclaimed in claim 156, wherein the phosphor-doped fluoroperovskitecompound is selected from the group consisting of: NaMgF₃:Eu²⁺;NaMgF₃:Pr³⁺; NaMgF₃:Tb³⁺; NaMgF₃:Mn²⁺; KMgF₃:Eu²⁺; RbMgF₃:Eu²⁺; andRbMgF₃:Ce^(3+.)